1. Field of the Invention
The present invention relates to an image forming system, a printer driver program, a processing controller and an image forming apparatus, and more particularly, to an image forming system capable of distributing image forming processing into a plurality of image forming apparatuses, a printer driver program adaptable to the aforementioned image forming systems, a processing controller adaptable to the aforementioned image forming system, an image forming apparatus adaptable to the aforementioned image forming system or an image forming commanding method.
Further, the present invention relates to a processing controller, an image forming apparatus and an image forming commanding methods.
2. Description of the Related Art
There have been known methods for distributing image forming processing to a plurality of image forming apparatuses connected to one another through a network or the like for realizing parallel processing, so-called tandem processing (for example, refer to Japanese Unexamined Patent Application No. 11-203082). Such tandem processing can shorten the time required for performing image forming processing.
The procedure for performing tandem processing with image forming apparatuses having such a tandem processing function is as follows, for example.
First, there will be described a tandem copying processing which is performed by a plurality of image forming apparatuses as copiers using the tandem processing function. On an operation panel of one of the copiers, a user selects a tandem function prepared as one of copying functions and then starts copying processing. Then, the copier reads the document images and performs copying processing while the document images are transferred to other copier which is intended to perform distributed processing. Then, the image forming apparatuses perform copying processing in parallel and output copies.
Next, there will be described a tandem printing processing which is performed by a plurality of image forming apparatuses as printers. On a driver screen of a host, a user selects a tandem function prepared as one of the printing functions, a main printer and a sub printer and starts printing processing. On receiving a command and data from the host, the main printer performs printing while the print data is also transferred to the sub printer which is intended to perform distributed processing. Then, the printers perform printing processing in parallel.
Whether or not tandem processing should be performed is determined on the basis of an explicit command from a user who intends to start copying or printing processing. However, if there are many items for setting copying or printing functions, a tandem-function setting menu is provided at a deeper level in the menu hierarchy, in many cases. In such cases, the tandem processing function can not be easily used by the user. Therefore, even though such a tandem function is provided, effective utilization of the function can not be expected.
Furthermore, even if the user explicitly selects the tandem function, the image forming apparatuses which are intended to perform distributed processing may be unavailable for image processing. In such a case, the user may start the tandem processing without noticing the state, which may result in unexpected processing.
Further, there may be cases as follows. In cases of processing a great number of copies or a great number of prints, the user can easily understand that the use of the tandem processing will shorten the processing time. However, in cases of processing a smaller number of copies or a smaller numbers of prints, it is difficult to understand whether or not the use of the tandem processing is more efficient than regular (non-tandem) processing. This is because the borderline thereof depends on the number of pages for each copy or print to be processed and the processing capacities of the image forming apparatuses intended to perform distributed processing and, therefore, can not be uniformly determined. The difficulty of the determination may cause the user to think the use of the tandem function inconvenient.